Note: None of these names are "official" in the lexicon of botnet research
All of these bot "types" can have different structures
by Sarah Nichols
Catfish bots exist to act like people. They aren't convincing, but they are there to stop users from getting too lonely and logging off. You'll typically see them in newer MMO games or sites where player satisfaction and investment are vital and they're still building a user base. Basically, they're dumb and not great company but we'd feel lonely without them
Puffins are also social animals and are known to mimic decoys in the wild. Image Source
Most tasks on MMOs or games can be repetitive and grind-heavy, having bots walking around, grinding away makes users want to fit in with the crowd. This type is similar to the Catfish, playing off of human social instincts, but is instead active and/or visible in a community.
You usually see these bots on reddit, they're there to perform a task like reminding you of an event, responding to a prompt or googling a fact. They keep things moving on the platform and help users out with tedious things that would otherwise take them away from the site
A Gif from the Tv show "The Office" demonstrating general chaos.
They exist to cause chaos and are not very good at anything else. They contain spam, broken code, etc. They've always been here and always will be. The platforms know this, can't stop it, and are the embodiment of this gif. No one can stop it. Everything is fine.
These bots mainly exist to increase views of marketing campaigns or misinfo & disinfo campaigns. They gamify site algorithms in order to make them 'work' for a certain price. The goal is to get as many people as possible to see the information they're hired to spread. Essentially they want the content to go viral. They typically use botnets and SEO in a combination of trial and error to help the content gain traction quickly.
A combination of mimic and amplification bots, these bots exist to amplify messages and pose as reasonably human-like, often making real people believe a message is more widely accepted or normalized. You usually see this with sponsored troll farms (aka. real people paid to tweet content), but it's possible with botnets too.